Chip on film, COF, that is, to fix an integrated chip, IC on a chip soft film of a flexible circuit board, FPC, in many display panels such as LCD, OLED, etc., this package technology chip is need to be used. This type of chip is used as a source driver and a gate driver of a display driver. In the driving circuit, one end of the COF is connected to a printed circuit board, PCB, and is responsible for receiving data signals transmitted from the printed circuit board. The other end of the COF is connected to a display panel for transmitting data signals output from the ICs to the display panel, to drive the display panel for performing display
Specifically, the connection between the COF and the printed circuit board and the display panel is accomplished through a bonding process. During the fabricating of the liquid crystal display, LCD, for the need of driving the liquid crystal, it is necessary to reserve the bonding position of the driving circuit. Conventionally, a thin film transistor, TFT substrate with a circuit is made larger than a color filter, CF substrate of an upper layer (usually larger than 1 mm) to expose the required bonding position of the lines, in order to reserve the bonding position of the driving lines, an outer bezel is needed to be disposed to cover the bonding region, so as not to be seen by the user and affect the appearance of the display.
In recent years, with the continuous development of LCD display industry, panel appearance has a trend to be gradually narrowing. For example, the narrow bezel TV is to narrow the edge of the non-display area, the bezel with a more concise, detailed shape, make the product more beautiful. Even the concept of a “bezel-less” panel is proposed. That is, the outer bezel of shielding the non-display area of the panel is removed, to achieve bezel-less display. However, since the bonding end of the TFT substrate is longer than the CF substrate, a special outer bezel needs to be reserved to cover the connection lines in the bonding region, affecting the narrow bezel, bezel-less display cannot be achieved.